Saturday, March 18, 2017

Sand's End

Past the towers of downtown Miami and over Biscayne Bay sits the city of Miami Beach. Perched on the tip of a narrow barrier island, Miami Beach is a resort community of just under 100,000 people, though its population swells with a steady stream of tourists. Through the wall of hotels that line its shore is the city's central draw: the wide, white stretch of Miami Beach's beach.

The beach is the centerpiece of the city’s promise of escape — escape from cold winters or college classes or family, where you can drink goblets of bright green liquor and cruise down Ocean Drive in a rented tangerine Lamborghini before retiring to the warm sand. To the casual observer, the beach may look like the only natural bit of the city, a fringe of shore reaching out from under the glass and pastel skyline. But this would be false: the beach is every bit as artificial as the towers and turquoise pools. For years the sea has been eating away at the shore, and the city has spent millions of dollars pumping up sand from the seafloor to replace it, only to have it wash away again. Every handful of sand on Miami Beach was placed there by someone.

That sand is washing away ever faster. The sea around Miami is rising a third of an inch a year, and it’s accelerating. The region is far from alone in its predicament, or in its response to an eroding coast: it’s becoming hard to find a populated beach in the United States that doesn’t require regular infusions of sand, says Rob Young, director of the Program for the Study of Developed Shorelines at Western Carolina University. Virginia Beach, North Carolina’s Outer Banks, New York’s Long Island, New Jersey’s Cape May, and countless other coastal cities are trapped in the same cycle, a cycle whose pace will become harder to maintain as the ocean rises.

"There isn’t a natural grain of sand on the beach in Northern New Jersey; there is no Miami Beach unless we build it," Young says. "The real endangered species on the coast of the US isn’t the piping plover or the loggerhead sea turtle. It’s an unengineered beach."

The sea has been slowly cutting a divot into the shore in front of Miami Beach’s iconic Fontainebleau hotel, encroaching nearly to the promenade. Patching it would normally be a small job. But Miami Beach has a problem, one more cities will soon face: it has run out of sand in the ocean nearby.

The beach is the tattered edge of the land. It’s made of debris, which we call sand when it’s too small to think about discretely, though exactly what it consists of varies. It could be pulverized coral, like in the Maldives, or crushed clamshells, like Shark Bay, Australia, or discarded glass, like around Fort Bragg, California. Often it’s rock that has been crushed by glaciers or eroded off mountains and washed down rivers to the sea. Beaches made from black basalt or purple garnet have a certain novelty value, but the ideal beach, the one you see on ads for airlines and beer, is sugary and white. It’s likely calcium carbonate or quartz.

Coastal engineers talk about "beach behavior," as if dealing with an unruly animal rather than a geologic feature. Waves sort sand grains to a depth where they no longer move them, so some beaches change with the seasons, as winter storms suck sand offshore, leaving only cobblestones, and smaller waves push it back in the summer. One thing all beaches have in common is that they’re always shifting, wave by wave over years or overnight, with a storm.

For much of the 20th century, people tried to hold beaches in place by building groins — lines of rock or wood pylons protruding from the shore. But groins robbed downdrift beaches of sand that would have come their way, creating new erosion problems. (Some came to be called "spite groins.") Seawalls made things worse, further blocking the natural movement of sand and forcing waves back onto the shore, scouring away the beach. By the 1970s, there was very little beach left on Miami Beach or shore at the Jersey Shore. So a new response became popular: add sand.

That job largely fell to the US Army Corps of Engineers. Dredges floated offshore, extending scoops or hoses tipped with cutter heads into the seafloor and piping sand back onto the eroding beach. Nourishment, as the practice is called, maintained the beach, but it was also an admission that there would never be a permanent solution to fixing the shore in place. Once you start nourishing a beach, you can never stop. Its equilibrium state lies elsewhere, and wave after wave will eat away at the shore, and you’ll keep having to find new sand to replace it.

Sand seems like an infinite resource, but it isn’t. You can’t put just any kind of sand on a beach. Forget about the thousands of miles of dunes in the Sahara and Gobi — rounded by wind, those grains are too smooth. Sand made by crushing rock is too jagged. Stones worn down by rivers and waves over millennia is ideal, but even then, it has to be the right type. If the grains are too small, they wash away quickly; too large, and the beach becomes a steep bank. If they’re the wrong density or wrong shape — say, plate-like shards of broken shells — they’ll float in the water, causing clouds. If the sand is too dark it will trap heat, and can shift the gender of sea turtles born there. "You want to match the native sand as close as you can," says Kevin Bodge, a coastal engineering consultant. "That sand was there for a reason."

Tremendous amounts of ocean sand gets used for land reclamation and construction. Countries use it to extend their borders, like Singapore and China, which has built seven new islands in the South China Sea. Billions of tons of sand gets poured into concrete. A United Nations report on sand shortages found that up to 60 billion tons of sand and gravel are mined each year, more than twice the amount moved by all the rivers in the world, which the report notes makes "humankind the largest of the planet’s transforming agents with respect to aggregates."

The United States has lined its coasts with over a billion cubic yards of sand, at a cost of $8.6 billion, according to a database maintained by Andy Coburn at Western Carolina University’s Program for the Study of Developed Shorelines. All that sand inevitably washes back into the sea. Sometimes waves bring it back, but for the most part, it’s lost to us; if it’s sucked out past a certain depth, it’s scattered along the continental shelf, too dispersed to be gathered back.

With sea levels rising, demand for beach sand is only going to grow. About 57 percent of the coast in the lower 48 states is already eroding, according to the USGS. "Every single coastal erosion problem we have right now is only going to get worse, not better," Young says. "It’s only going to erode faster, not slower, require more sand, not less." Gradually now, but soon overwhelmingly, every coastline is going to want to move inland. Young foresees a future of rising costs and conflict over diminishing sand. "If you want to invest, buy a dredge."

No state requires more sand than Florida, which sits in the middle of hurricane alley and has the longest coastline after Alaska. Half of the 825 miles of beaches monitored by the state’s Department of Environmental Protection are designated as critically eroding, from Daytona Beach to the Kennedy Space Center on Cape Canaveral to the shore in front of Mar-a-Lago, the Palm Beach estate of President-elect Donald Trump.

On July 31st, 2015, the Army Corps released a plan for patching eroding sections of Miami Beach. Miami-Dade’s sand resources had been exhausted, the Corps wrote, and some of the best alternatives lay to the north, offshore of Martin and St. Lucie counties. Though the shoals were in federal waters and the northern counties had no greater right to them than anyone else, they viewed the sand as theirs, and with the Corps’ announcement began the latest skirmish in what local officials call "the sand wars."

State Senator Joe Negron, whose district includes parts of Martin and St. Lucie, swore that Miami-Dade "wouldn’t get a single grain." Frannie Hutchinson, a St. Lucie commissioner, demanded the Corps "take its shovels and buckets and go home." She filed 15 public comments on the Corps’ proposal, saying that it failed to address sea level rise and would rob St. Lucie of needed sand. The county erosion chair for 14 years, Hutchinson says that she cringes every time she sweeps dirt out of her house. "Do you know how much sand is in there? You can’t replace sand."

There was a sense, in council meetings and public statements, that Miami Beach was reaping what it sowed, and that with the sea rising, it was every county for itself. "They’ve squandered their sand, they’ve overdeveloped, they’ve depleted their resources and now they want to come and take ours," says Sarah Heard, a Martin County Commissioner. "We need to protect that offshore site, we need to guard it very carefully. We don’t know exactly how sea level rise is going to impact us, but we know it’s accelerating rapidly, we know there’s going to be inundation."

Heard is a Republican, but laments her party’s denial of climate change. (Last year, the Florida Center for Investigative Reporting found that the state's governor, Rick Scott, forbid state officials from using the term in emails or reports.) Jacqui Thurlow-Lippisch, another Martin County commissioner who objected to the Corps plan, is also a Republican, and also clear-eyed about what rising seas will do to her community. Just as there are proverbially no atheists in foxholes, it’s increasingly difficult to be a local politician in coastal Florida and deny the sea is rising.

Yet what to do about it at a local level is a conundrum. Right now, the answer is to keep piling on more sand. Thurlow-Lippisch describes nourishment as a loop her town is trapped in: the most expensive property is on the beach, she says, and letting it fall into the sea would rob her county of 30 percent of its tax base, making it impossible to fund schools, run buses, and provide lunches for children in need. Though she wonders whether she’s doing the right thing, she continues to fight for the sand that her community will eventually have to put on its shore. "We all have to look ourselves in the mirror and ask, is this a sustainable life? What are we doing here? But right now, we’re in it, we’re doing it."

As the northern counties lobbed angry missives at the Corps, one alternative kept coming up: the Bahamas.

The nearest Bahamian islands are just 50 miles east of Miami. The sand grains there aren’t rock, but orbs of calcium carbonate called aragonite, which some scientists believe is formed by bacteria as deep ocean water moves into the warm, shallow banks of the Caribbean. The exact process that produces the sand is poorly understood, says Lisa Robbins, an oceanographer who studies it, and occurs in only a few other places in the world, such as the Arabian Gulf.

One thing is clear: it’s premium stuff. "They’re not only mysterious, they’re gorgeous, and wonderful to step on," Robbins says of the grains, which she likens to "little pearls." The sand is so white that when coastal engineer Kevin Bodge brought in a barge’s worth in the early ‘90s for Fisher Island, a wealthy community willing to pay for it, the customs official looked on incredulously.

"It was 1991," Bodge recalls, "the height of the Miami Vice thing, so we had to clear customs, and it came in on a barge and when the sun hit that thing coming over the horizon in the early morning light, it was the most incredible pile of gleaming white powder I’ve ever seen. The customs agent just looked at me and said, ‘You gotta be kidding me.’"

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